Method for making organic light emitting diode array

ABSTRACT

The disclosure relates to a method of making organic light emitting diode array. A base defining a plurality of convexities is provided. A number of first electrodes are applied on the plurality of convexities. A number of red light electroluminescent layers are transfer printed on a first group of the first electrodes. A number of green light electroluminescent layers are transfer printed on a second group of the first electrodes. A number of blue light electroluminescent layers are transfer printed on a third group of the first electrodes. A patterned second insulative layer is made to cover the number of first electrodes and expose the electroluminescent layers. A second electrode is electrically connected to the electroluminescent layers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No.201310724055.2 filed on Dec. 25, 2013 in the China Intellectual PropertyOffice, the contents of which are incorporated by reference herein.

FIELD

The subject matter herein generally relates to organic light emittingdiode (OLED) arrays and method for making the same.

BACKGROUND

Organic light emitting diodes are a type of light emitting diode that ismade of thin films of organic molecules. A display screen using theorganic light emitting diodes need no back light source, can saveelectric energy, and has greater angle of visibility. Thus, the organiclight emitting diodes attract more and more attention.

A conventional method for making the organic light emitting diodes is tomake a plurality of organic light emitting diodes on a substrate to forman array. The method includes: forming a thin-film transistor (TFT)array on the substrate; applying a first insulative layer on thethin-film transistor array; forming a plurality of first electrodes onthe first insulative layer; applying a second insulative layer on thefirst insulative layer to cover the edges of each of plurality of firstelectrodes to expose the middle portion of each of plurality of firstelectrodes; depositing an organic light emitting layer on the middleportion of each of plurality of first electrodes; and making a secondelectrode on the organic light emitting layer. However, the organiclight emitting layer is formed usually by vacuum evaporation which needsmask, high temperature, and vacuum device. Thus, the method iscomplicated and high cost.

What is needed, therefore, is to provide an organic light emitting diodearrays and method for making the same which can overcome theshortcomings as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof example only, with reference to the attached figures, wherein:

FIG. 1 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 2 is a schematic view of one embodiment of a plurality ofconvexities arranged in a two-dimensional array.

FIG. 3 is a schematic view of one embodiment of a plurality ofstrip-shaped convexities arranged in a one-dimensional array.

FIG. 4 is a flow chart of one embodiment of a method for making a firstelectrode of an organic light emitting diode array.

FIG. 5 is a flow chart of one embodiment of a method for making anorganic light emitting layer of an organic light emitting diode array.

FIG. 6 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 7 is a schematic view of one embodiment of an organic lightemitting layer.

FIG. 8 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 9 is a flow chart of one embodiment of a method for making anorganic red light emitting layer of an organic light emitting diodearray.

FIG. 10 is a flow chart of one embodiment of a method for making anorganic green light emitting layer of an organic light emitting diodearray.

FIG. 11 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 12 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 13 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 14 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 15 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 16 is a top view of the flow chart of FIG. 15.

FIG. 17 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 18 is a flow chart of one embodiment of a method for making a holetransport layer with different thickness by transfer printing once time.

FIG. 19 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 20 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 21 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 22 is a flow chart of one embodiment of a method for making a holeinjection layer and a hole transport layer with different thickness bytransfer printing once time.

FIG. 23 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 24 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 25 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 26 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 27 is a schematic view of one embodiment of an organic lightemitting diode array.

FIG. 28 is an exploded view of one embodiment of the organic lightemitting diode array of FIG. 27.

FIG. 29 is a flow chart of one embodiment of a method for making anorganic light emitting diode array.

FIG. 30 is an exploded view of one embodiment of an organic lightemitting diode array.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures and components have notbeen described in detail so as not to obscure the related relevantfeature being described. The drawings are not necessarily to scale andthe proportions of certain parts may be exaggerated to better illustratedetails and features. The description is not to be considered aslimiting the scope of the embodiments described herein.

Several definitions that apply throughout this disclosure will now bepresented.

The term “coupled” is defined as connected, whether directly orindirectly through intervening components, and is not necessarilylimited to physical connections. The connection can be such that theobjects are permanently connected or releasably connected. The term“outside” refers to a region that is beyond the outermost confines of aphysical object. The term “inside” indicates that at least a portion ofa region is partially contained within a boundary formed by the object.The term “substantially” is defined to be essentially conforming to theparticular dimension, shape or other word that substantially modifies,such that the component need not be exact. For example, substantiallycylindrical means that the object resembles a cylinder, but can have oneor more deviations from a true cylinder. The term “comprising” means“including, but not necessarily limited to”; it specifically indicatesopen-ended inclusion or membership in a so-described combination, group,series and the like. It should be noted that references to “an” or “one”embodiment in this disclosure are not necessarily to the sameembodiment, and such references mean at least one.

The present disclosure is described in relation to organic lightemitting diode arrays and methods for making the same. The organic lightemitting diode array includes a base having a plurality of convexities,and a plurality of organic light emitting diodes located on theplurality of convexities. Each of the plurality of organic lightemitting diodes can include a hole injection layer (HIL), a holetransport layer (HTL), an electroluminescent layer (EL), an electrontransport layer (ETL), and an electron injection layer (EIL) stackedwith each other in that order. The hole injection layer, the holetransport layer, the electron transport layer, and the electroninjection layer are optional. The plurality of organic light emittingdiodes can share a common hole injection layer, hole transport layer,electron transport layer, and/or the electron injection layer. Theorganic light emitting diode array can be an active matrix type orpassive matrix type. The number of the organic light emitting diodes ineach organic light emitting diode array is not limited. Each of theplurality of organic light emitting diodes can be used as a pixel unit.Each of the plurality of organic light emitting diodes can also be usedas a sub-pixel, and three of the plurality of organic light emittingdiodes form a pixel unit.

The plurality of organic light emitting diodes can be made on theplurality of convexities by transfer printing. In some embodiments, atleast one of the hole injection layer, the hole transport layer, theelectroluminescent layer, the electron transport layer, and the electroninjection layer can be made by transfer printing. Especially, the holeinjection layer, the hole transport layer, the electroluminescent layerare made by transfer printing, and the electron transport layer and theelectron injection layer are made by vacuum evaporation because thewetting process may change the property of the electron injection layer.The material for transfer printing is coated on a template first andthen transfer printed from the template to the plurality of convexitiesto form a plurality of layer-shaped elements. The material for transferprinting can be transfer printed to form a plurality of layer-shapedelements with the same or different thickness or heights. The pluralityof layer-shaped elements can be transfer printed on all of the pluralityof convexities once time, twice time, or more than twice time.

FIG. 1 illustrates a method of one embodiment for making an organiclight emitting diode array 10. The method includes following steps:

step (S10), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; the first insulative layer 106 defines a plurality ofconvexities 108 on a surface opposite to the plurality of thin-filmtransistors 104;

step (S11), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein each of the plurality of first electrodes110 is located on and electrically connected to one of the plurality ofthin-film transistors 104;

step (S12), applying a plurality of organic light emitting layers 120 onthe plurality of first electrodes 110;

step (S13), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 and expose part of each of theplurality of organic light emitting layers 120; and step (S14),electrically connecting a second electrode 130 to the plurality oforganic light emitting layers 120.

In step (S10), the material of the substrate 102 can be glass, ceramic,silicon dioxide (SiO₂), silicon nitride (SiN) or polymer. The pluralityof thin-film transistors 104 can be made of semiconductor such assilicon, gallium arsenide (GaAs), gallium nitride (GaN), or carbonnanotubes (CNTs). In one embodiment, the substrate 102 is a silicondioxide layer on a wafer, and the plurality of thin-film transistors 104are made on the wafer similar to that used to make semiconductor device.

The first insulative layer 106 covers all of the plurality of thin-filmtransistors 104. The first insulative layer 106 can be configured toprovide a smooth surface for making the plurality of organic lightemitting diodes and insulate the plurality of organic light emittingdiodes from the plurality of thin-film transistors 104. The firstinsulative layer 106 can be made of organic insulative material orinorganic insulative material. The thickness of the first insulativelayer 106 can be in a range from about 1 micrometer to about 50micrometers. In one embodiment, the thickness of the first insulativelayer 106 is in a range from about 1 micrometer to about 15 micrometers.The first insulative layer 106 can be made by depositing, transferprinting or spin coating.

The plurality of convexities 108 can be arranged in a two-dimensionalarray as shown in FIG. 2. The shape of the convexity 108 can be selectedaccording to need, as long as the convexity 108 has a smooth top surface109. Each of the plurality of convexities 108 can be a frustum of acone, a cuboid, or a cube, namely, the smooth top surface 109 can becircular, square, or rectangular. The smooth top surface 109 can be aplanar surface or a curved surface such as concave spherical or convexspherical. When the smooth top surface 109 is a curved surface, theorganic light emitting layer 120 can have a greater area, and the angleof the emergent light of the organic light emitting layer 120 can beadjusted by changing the curvature of the smooth top surface 109. Thesize of the convexity 108 can be selected according to pixel unit of theorganic light emitting diode array 10, for example, from tensmicrometers to hundreds micrometers. The plurality of convexities 108can be made by printing, etching, or stamping. When the first insulativelayer 106 is made of organic insulative material, the plurality ofconvexities 108 can be made by stamping. When the first insulative layer106 is made of inorganic insulative material, the plurality ofconvexities 108 can be made by etching. The plurality of convexities 108can also be arranged in a one-dimensional array as shown in FIG. 3. Eachof the plurality of convexities 108 is strip-shaped, and the pluralityof convexities 108 are in parallel with each other. In one embodiment,the plurality of convexities 108 are a plurality of cuboids arranged ina two-dimensional array, and the plurality of convexities 108 arelocated corresponding to the plurality of thin-film transistors 104 in aone-to-one manner.

In step (S11), the plurality of first electrodes 110 are paced andinsulated from each other. The plurality of first electrodes 110 areelectrical conductive layers and made of conductive oxide, such asindium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide(AZO), zinc oxide (ZnO) or tin oxide (TO), or metal such as gold,silver, aluminum, magnesium or alloy thereof. Each of the plurality offirst electrodes 110 is located at least on the smooth top surface 109of the corresponding convexity 108. In one embodiment, each of theplurality of first electrodes 110 is coated on both the smooth topsurface 109 and side surfaces of the corresponding convexity 108. Theplurality of first electrodes 110 can be formed by directly depositingthrough a mask. The plurality of first electrodes 110 can also be formedby depositing a continuous conductive layer to cover all the pluralityof convexities 108 first, and then patterning the continuous conductivelayer by etching to obtain the plurality of first electrodes 110. Atleast part of each of the plurality of first electrodes 110 is locatedon the smooth top surface 109 of the corresponding convexity 108 so thateach first electrode 110 has a protrudent surface. The protrudentsurface can be used to transfer print the plurality of organic lightemitting layers 120.

FIG. 4 illustrates a method of one embodiment for making the pluralityof first electrodes 110. The method includes following steps:

step (S110), exposing part of each of the plurality of thin-filmtransistors 104 by etching the base 100 from the first insulative layer106;

step (S111), depositing a continuous conductive layer 112 to cover allthe plurality of convexities 108 and electrically connect to theplurality of thin-film transistors 104;

step (S112), patterning the continuous conductive layer 112 to obtainthe plurality of first electrodes 110 spaced from each other, whereineach of the plurality of first electrodes 110 corresponds to and iselectrically connected to one of the plurality of thin-film transistors104; and step (S113), making a patterned third insulative layer 142between the plurality of first electrodes 110 so that adjacent two ofthe plurality of first electrodes 110 are insulated from each other andthe part of the plurality of first electrodes 110 on the smooth topsurfaces 109 are exposed.

In step (S110), the etching method can be selected according to thematerial of the first insulative layer 106 and the thin-film transistors104. A plurality of openings 107 are formed to corresponding theplurality of thin-film transistors 104 so that at least part of each ofthe plurality of thin-film transistors 104 is exposed.

In step (S111), the method for depositing the conductive layer 112 canbe selected according to need, for example, sputtering, chemical vapordeposition, or thermal deposition. The conductive layer 112 can bedeposited in to the plurality of openings 107 to electrically connect tothe plurality of thin-film transistors 104. In one embodiment, thedepositing the conductive layer 112 includes: depositing a first indiumtin oxide layer; applying a silver layer on the first indium tin oxidelayer; and depositing a second indium tin oxide layer on the silverlayer. Thus, an ITO/Ag/ITO composite conductive layer 112 is formed.Because the silver metal layer is sandwiched between two indium tinoxide layers, the metal layer can prevent oxidation.

In step (S112), the patterning the continuous conductive layer 112 canbe performed by etching through a mask. The pattern of the plurality offirst electrodes 110 can be designed according to need.

In step (S113), the patterned third insulative layer 142 can be formedby directly depositing through a mask. The patterned third insulativelayer 142 can be formed by depositing a continuous insulative layer tocover the plurality of first electrodes 110 and then removing part ofthe continuous insulative layer to expose the part of the plurality offirst electrodes 110 on the smooth top surfaces 109. When the conductivelayer 112 is ITO/Ag/ITO composite, the metal layer will be exposed onedge during patterning the conductive layer 112. The patterned thirdinsulative layer 142 can cover the edge of the plurality of firstelectrodes 110 to protect the exposed metal layer of the ITO/Ag/ITOcomposite. The patterned third insulative layer 142 can also prevent theplurality of first electrodes 110 from being broken or electricallyconnected with each other in following process. The step (S113) isoptional.

In step (S12), the plurality of organic light emitting layers 120 aremade my transfer printing. In one embodiment, as shown in FIG. 5, eachof the plurality of organic light emitting layers 120 only includes anelectroluminescent layer 125. The plurality of organic light emittinglayers 120 are made by following steps:

step (S120), applying an organic electroluminescent film 1252 on asurface 1502 of a first template 150;

step (S121), contacting the protrudent surfaces of the plurality offirst electrodes 110 with the organic electroluminescent film 1252; andstep (S122), separating the plurality of first electrodes 110 from thefirst template 150.

In step (S120), the material, size and shape of the first template 150can be selected or designed according to need. The material of theorganic electroluminescent film 1252 can be any organicelectroluminescent high or low molecular materials that can be made into solution, such as polyfluorene (PF). The thickness of the organicelectroluminescent film 1252 can be in a range from about tensnanometers to about hundreds nanometers, for example, from about 50nanometers to about 300 nanometers. The organic electroluminescent film1252 can be applied on the surface 1502 of the first template 150 byspin-coating, spray-coating, brush-coating, or immerse-coating. In oneembodiment, the first template 150 is a planar polydimethylsiloxane(PDMS) substrate with low surface free energy, and the organicelectroluminescent film 1252 is coated on the entire surface 1502.

Furthermore, a wetting layer (not shown) can be applied on the surface1502 of the first template 150 before applying the organicelectroluminescent film 1252. Thus, the organic electroluminescent film1252 is easy to be coated and transferred. The wetting layer can be ahigh volatile solvent coated on the surface 1502, such as toluene. Thewetting layer can also be a plurality of high reactive functional groupsformed by treating the surface 1502. For example, a plurality ofcarboxyl group (—COOH) or hydroxyl group (—OH) can be formed on thesurface 1502 of the polydimethylsiloxane first template 150 by oxygenplasma treating.

In step (S121), a pressure can be applied on the base 100 in the processof contacting the protrudent surfaces of the plurality of firstelectrodes 110 with the organic electroluminescent film 1252. Becausethe plurality of first electrodes 110 are located on the plurality ofconvexities 108 and the organic electroluminescent film 1252 is formedon the planar surface 1502, it is easy to transfer print and does notneed to align the plurality of first electrodes 110 with the organicelectroluminescent film 1252.

In step (S122), a plurality of electroluminescent layers 125 are formedon the protrudent surfaces of the plurality of first electrodes 110 andused as the plurality of organic light emitting layers 120.

Furthermore, a heating can be applied on the first template 150 in theprocess of separating the plurality of first electrodes 110 from thefirst template 150. Thus, the plurality of first electrodes 110 and thefirst template 150 may have different temperature, and the adhesionstrength between the organic electroluminescent film 1252 and theplurality of first electrodes 110 is stronger than the adhesion strengthbetween the organic electroluminescent film 1252 and the first template150.

Because the plurality of electroluminescent layers 125 have the samematerial, the organic light emitting diode array 10 is a monochromaticorganic light emitting diode array. Each of the plurality of organiclight emitting layer 120 can be a single layer of organicelectroluminescent material that can luminesce red light, green light,blue light, or white light. Each of the plurality of organic lightemitting layer 120 can also be a multi-layer structure of differentorganic electroluminescent materials that can be made by repeatingembodiment of the method of FIG. 5. For example, each of the pluralityof organic light emitting layer 120 includes red lightelectroluminescent layer, a green light electroluminescent layer, and ablue light electroluminescent layer stacked with each other.

Furthermore, a hole injection layer 122 and a hole transport layer 124can be formed on the plurality of first electrodes 110 before thetransfer printing the plurality of electroluminescent layers 125. Also,an electron transport layer 126 and an electron injection layer 128 canbe formed on surfaces of the plurality of electroluminescent layers 125after the transfer printing the plurality of electroluminescent layers125. The hole injection layer 122, the hole transport layer 124, theelectron transport layer 126, and the electron injection layer 128 canbe made by the transfer printing method of FIG. 5, or by the vacuumevaporation. The material of the hole injection layer 122 suitable fortransfer printing can be PEDOT:PSS. The PEDOT:PSS is a water solution ofa polymer consisting of PEDOT and PSS. The PEDOT isPoly(3,4-ethylenedioxythiophene). The PSS is poly(styrenesulfonate). Thematerial of the hole transport layer 124 suitable for transfer printingcan be polyaniline (PAN).

When the hole injection layer 122, the hole transport layer 124, theelectron transport layer 126, and the electron injection layer 128 aremade by the vacuum evaporation, the hole injection layer 122, each ofthe hole transport layer 124, the electron transport layer 126, and theelectron injection layer 128 can be a continuous layer. Namely, theplurality of organic light emitting layers 120 have a common holeinjection layer 122, a common hole transport layer 124, a commonelectron transport layer 126, and a common electron injection layer 128.When the hole injection layer 122, the hole transport layer 124, theelectron transport layer 126, and the electron injection layer 128 aremade by the transfer printing method of FIG. 5, each of the holetransport layer 124, the electron transport layer 126, and the electroninjection layer 128 is a patterned structure with a plurality of layersspaced from each other. Namely, each of the plurality of organic lightemitting layers 120 has an independent hole injection layer 122, anindependent hole transport layer 124, an independent electron transportlayer 126, and an independent electron injection layer 128.

In step (S13), the patterned second insulative layer 140 can be formedby directly depositing through a mask. The patterned second insulativelayer 140 can also be formed by depositing a continuous insulative layerto cover the plurality of first electrodes 110 and the plurality oforganic light emitting layers 120, and then removing the part of thecontinuous insulative layer to expose a part of each of the plurality oforganic light emitting layers 120. The patterned second insulative layer140 can be made of the same or different material as the firstinsulative layer 106. The patterned second insulative layer 140 caninsulate adjacent two of the plurality of first electrodes 110 andprevent the plurality of first electrodes 110 from being electricallyconnected with the second electrode 130 in following process. Becausethe plurality of first electrodes 110 are covered by the plurality oforganic light emitting layers 120, the patterned second insulative layer140 only need to be coated on the first electrode 110 between adjacenttwo of the plurality of convexities 108 or on the side surfaces of theplurality of convexities 108. In one embodiment, the patterned secondinsulative layer 140 and the plurality of organic light emitting layers120 have a common planar surface so that the second electrode 130 iseasy to be formed.

In step (S14), the second electrode 130 is an electrical conductivelayer and made of conductive oxide, such as indium tin oxide, indiumzinc oxide, aluminum zinc oxide, zinc oxide or tin oxide, or metal suchas gold, silver, aluminum, magnesium or alloys thereof. The secondelectrode 130 can be a continuous conductive layer, namely, the organiclight emitting diode array 10 shares a common second electrode. Thesecond electrode 130 can also be a patterned structure, namely, aplurality of second electrodes 130 are located. Each of the plurality ofsecond electrodes 130 is located corresponding to a single one of theplurality of organic light emitting layers 120 or one row of theplurality of organic light emitting layers 120. The second electrode 130can be formed by sputtering, vacuum evaporation, transfer printing, orspin coating to cover all of the patterned second insulative layer 140and the plurality of organic light emitting layers 120. The secondelectrode 130 can also be formed on the corresponding one of theplurality of organic light emitting layers 120 by screen printing ormask depositing. In one embodiment, the second electrode 130 is acontinuous indium tin oxide film with a thickness of about 100micrometers.

Furthermore, a step of applying an insulative protecting layer on thesecond electrode 130 to package the organic light emitting diode array10 can be performed.

FIG. 6 illustrates an organic light emitting diode array 10 of oneembodiment. The organic light emitting diode array 10 includes a base100, a plurality of first electrodes 110, a plurality of organic lightemitting layers 120, a patterned second insulative layer 140, and asecond electrode 130. The base 100 includes a substrate 102, a pluralityof thin-film transistors 104 located on a surface of the substrate 102and arranged to form an array, and a first insulative layer 106 locatedon a surface of the plurality of thin-film transistors 104. The firstinsulative layer 106 defines a plurality of convexities 108 on a surfaceopposite to the plurality of thin-film transistors 104. The plurality offirst electrodes 110 and the plurality of thin-film transistors 104 arelocated and electrically connected with each other in a one-to-onemanner. Each of the plurality of first electrodes 110 is located on thetop surface and side surfaces of the corresponding one of the pluralityof convexities 108. Part of the plurality of first electrodes 110 extendto the surface of the first insulative layer 106 exposed from adjacenttwo of the plurality of convexities 108. The plurality of organic lightemitting layers 120 are located on the surfaces of the plurality offirst electrodes 110 and electrically connected with the plurality offirst electrodes 110 in a one-to-one manner. The patterned secondinsulative layer 140 cover the plurality of first electrodes 110 andexpose the plurality of organic light emitting layers 120. The secondelectrode 130 covers the patterned second insulative layer 140 and theplurality of organic light emitting layers 120.

Referring to FIG. 7, each of the plurality of organic light emittinglayers 120 can include a hole injection layer 122, a hole transportlayer 124, an electroluminescent layer 125, an electron transport layer126, and an electron injection layer 128. The hole injection layer 122,the hole transport layer 124, the electroluminescent layer 125, theelectron transport layer 126, and the electron injection layer 128 arestacked with each other in that order from the first electrode 110 tothe second electrode 130 or from the second electrode 130 to the firstelectrode 110. Each of the hole injection layer 122, the hole transportlayer 124, the electron transport layer 126, and the electron injectionlayer 128 can be located only corresponding to one of the plurality offirst electrodes 110. Each of the hole injection layer 122, the holetransport layer 124, the electron transport layer 126, and the electroninjection layer 128 can also be a continuous layer to cover all of theplurality of first electrodes 110.

The organic light emitting diode array 10 is a monochromatic organiclight emitting diode array. Embodiments of full color organic lightemitting diode array are provided below. Only one pixel unit is shown inthe FIGS. Each of the pixel unit includes a red light organic lightemitting diode, a green light organic light emitting diode, and a bluelight organic light emitting diode. The red light organic light emittingdiode, the green light organic light emitting diode, and the blue lightorganic light emitting diode are used as three sub-pixels.

FIG. 8 illustrates a method of one embodiment for making an organiclight emitting diode array 20. The method includes following steps:

step (S20), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; and the first insulative layer 106 defines a pluralityof convexities 108 on a surface opposite to the plurality of thin-filmtransistors 104;

step (S21), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein each of the plurality of first electrodes110 is located corresponding to and electrically connected to one of theplurality of thin-film transistors 104;

step (S22), applying a plurality of organic light emitting layers 120 onthe plurality of first electrodes 110, wherein adjacent three of theplurality of organic light emitting layers 120 have different organicelectroluminescent materials;

step (S23), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 and expose part of each of theplurality of organic light emitting layers 120; and

step (S24), electrically connecting a second electrode 130 to theplurality of organic light emitting layers 120.

The method for making the organic light emitting diode array 20 issimilar to the method for making the organic light emitting diode array10 except that in step (S22), three organic light emitting layers 120 ofthe same pixel unit have different organic electroluminescent materialsthat can luminesce light of different color. In one embodiment, a redlight organic light emitting layer 120, a green light organic lightemitting layer 120, and a blue light organic light emitting layer 120are transfer printed on adjacent three of the plurality of firstelectrodes 110. Thus, the organic light emitting diode array 20 canachieve full color display.

In one embodiment, the red light organic light emitting layer 120, thegreen light organic light emitting layer 120, and the blue light organiclight emitting layer 120 of the same pixel unit can have differentthickness. In one embodiment, one of the red light organic lightemitting layer 120, the green light organic light emitting layer 120,and the blue light organic light emitting layer 120 of the same pixelunit can have different thickness with the other two. Because the redlight, green light and the blue light have different transmittancethrough the organic light emitting layer 120, the second electrode layer130 and other package layer, the different thickness of the organiclight emitting layers 120 allows the red light, the green light and theblue light to be mixed uniformly.

FIGS. 9-10 illustrates a method of one embodiment for transfer printingthree different color organic light emitting layers 120 on threeadjacent first electrodes 110. The method includes following steps:

step (S220), applying a red light organic electroluminescent film 1252on a surface of a second template 152;

step (S221), contacting the first one of the three first electrodes 110with the red light organic electroluminescent film 1252;

step (S222), separating the first one of the three first electrodes 110from the second template 152 so that a red light organic light emittinglayer 120 is formed on the first one of the three first electrodes 110;

step (S223), applying a green light organic electroluminescent film 1252on a surface of a third template 154;

step (S224), contacting the second one of the three first electrodes 110with the green light organic electroluminescent film 1252;

step (S225), separating the second one of the three first electrodes 110from the third template 154 so that a green light organic light emittinglayer 120 is formed on the second one of the three first electrodes 110;and step (S226), transfer printing a blue light organic light emittinglayer 120 on the third one of the three first electrodes 110 by theprocess above.

In step (S221), the second one and third one of the three firstelectrodes 110 are not in contact with the red light organicelectroluminescent film 1252. The step (S221) can be achieved by onlyapplying the red light organic electroluminescent film 1252 on part ofthe second template 152 corresponding to the first one of the threefirst electrodes 110, covering the red light organic electroluminescentfilm 1252 corresponding to the second one and third one of the threefirst electrodes 110, or allowing red light organic electroluminescentfilm 1252 have different heights. In one embodiment, the second template152 has a first surface 1522 and a second surface 1524. The firstsurface 1522 and the second surface 1524 have different heights so thatthe red light organic electroluminescent film 1252 on the secondtemplate 152 has different heights. Because the red light organicelectroluminescent film 1252 has a uniform thickness, the red lightorganic electroluminescent film 1252 on the first surface 1522 is higherthan the red light organic electroluminescent film 1252 on the secondsurface 1524. When the first one of the three first electrodes 110touches the red light organic electroluminescent film 1252 on the firstsurface 1522, the second one and third one of the three first electrodes110 are spaced from the red light organic electroluminescent film 1252on the second surface 1524.

In step (S224), the red light organic light emitting layer 120 and thethird one of the three first electrodes 110 are not in contact with thegreen light organic electroluminescent film 1252. In one embodiment, thethird template 154 has a third surface 1542 and a fourth surface 1544.The third surface 1542 and the fourth surface 1544 have differentheights so that the green light organic electroluminescent film 1252 onthe third template 154 has different heights. Because the green lightorganic electroluminescent film 1252 has a uniform thickness, the greenlight organic electroluminescent film 1252 on the third surface 1542 ishigher than the green light organic electroluminescent film 1252 on thefourth surface 1544. When the second one of the three first electrodes110 touches the green light organic electroluminescent film 1252 on thethird surface 1542, the red light organic light emitting layer 120 andthe third one of the three first electrodes 110 are spaced from thegreen light organic electroluminescent film 1252 on the fourth surface1544. The height difference between the third surface 1542 and thefourth surface 1544 is greater than the height difference between thefirst surface 1522 and the second surface 1524.

FIG. 11 illustrate an organic light emitting diode array 20 of oneembodiment. The organic light emitting diode array 20 includes a base100, a plurality of first electrodes 110, a plurality of organic lightemitting layers 120, a patterned second insulative layer 140, and asecond electrode 130. The organic light emitting diode array 20 issimilar to the organic light emitting diode array 10 except that threeorganic light emitting layers 120 of the same pixel unit includes a redlight organic light emitting layer 120, a green light organic lightemitting layer 120, and a blue light organic light emitting layer 120.Thus, the organic light emitting diode array 20 can achieve full colordisplay.

In one embodiment, the red light organic light emitting layer 120, thegreen light organic light emitting layer 120, and the blue light organiclight emitting layer 120 of the same pixel unit can have differentthickness. Because the protrudent surfaces of the three first electrodes110 have the same height, the surfaces of the red light organic lightemitting layer 120, the green light organic light emitting layer 120,and the blue light organic light emitting layer 120 that is opposite tothe three first electrodes 110 have different heights. The surface ofthe patterned second insulative layer 140 that is opposite to the base100 can be flushed with any one of the surfaces of the red light organiclight emitting layer 120, the green light organic light emitting layer120, and the blue light organic light emitting layer 120 that isopposite to the three first electrodes 110. In one embodiment, thesurface of the patterned second insulative layer 140 that is opposite tothe base 100 is flushed with the surface of the red light organic lightemitting layer 120. The green light organic light emitting layer 120 andthe blue light organic light emitting layer 120 extends out of thepatterned second insulative layer 140 and are embedded in to the secondelectrode 130.

FIG. 12 illustrate an organic light emitting diode array 20A of anotherembodiment. In the organic light emitting diode array 20A, the organiclight emitting layer 120 includes a hole injection layer 122, a holetransport layer 124, an electroluminescent layer 125, an electrontransport layer 126, and an electron injection layer 128. The holeinjection layer 122 and the hole transport layer 124 are located betweenthe first electrode 110 and the electroluminescent layer 125. The holeinjection layer 122 and the hole transport layer 124 have the samethickness and heights. The electroluminescent layers 125 have differentthickness and heights. The electron transport layer 126 and the electroninjection layer 128 are located between the electroluminescent layer 125and the second electrode 130. The electron transport layer 126 and theelectron injection layer 128 have the same thickness and differentheights. The surface of the patterned second insulative layer 140 thatis opposite to the base 100 is flushed with the highest surface of theelectron injection layer 128. A part of the second electrode 130 isembedded in to the patterned second insulative layer 140 and in directcontact with the other two electron injection layers 128. The organiclight emitting layer 120 of FIG. 12 can be made by making the holeinjection layer 122 and the hole transport layer 124 on the firstelectrodes 110 via the method of FIG. 5 or vacuum evaporation; transferprinting the electroluminescent layers 125 by the method of FIGS. 9-10;and making the electron transport layer 126 and the electron injectionlayer 128 by or vacuum evaporation.

Referring to FIG. 13 illustrates a method of one embodiment for makingan organic light emitting diode array 30. The method includes followingsteps:

step (S30), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; the first insulative layer 106 defines a plurality ofconvexities 108 on a surface opposite to the plurality of thin-filmtransistors 104;

step (S31), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein each of the plurality of first electrodes110 is located corresponding to and electrically connected to one of theplurality of thin-film transistors 104;

step (S32), making a patterned second insulative layer 140 to coverparts of the plurality of first electrodes 110 between the plurality ofconvexities 108 and expose protrudent surfaces of the plurality of firstelectrodes 110 on the smooth top surfaces 109 of the plurality ofconvexities 108;

step (S33), applying a plurality of organic light emitting layers 120 onthe plurality of first electrodes 110, wherein adjacent three of theplurality of organic light emitting layers 120 have different organicelectroluminescent materials; and

step (S34), electrically connecting a second electrode 130 to theplurality of organic light emitting layers 120.

The method for making the organic light emitting diode array 30 issimilar to the method for making the organic light emitting diode array20 except that the patterned second insulative layer 140 is appliedbefore the plurality of organic light emitting layers 120, and the threeorganic light emitting layers 120 of the same pixel unit have the samethickness.

In step (S32), because the patterned second insulative layer 140 isapplied before the plurality of organic light emitting layers 120, itcan prevent the plurality of organic light emitting layers 120 frombeing damaged and polluted when the patterned second insulative layer140 is made by etching. The surface of the patterned second insulativelayer 140 can be flushed with the smooth top surfaces 109 of theplurality of convexities 108.

In step (S33), because parts of the plurality of first electrodes 110 onthe smooth top surfaces 109 of the plurality of convexities 108 areexposed and protruded out of the patterned second insulative layer 140,the plurality of organic light emitting layers 120 can be transferprinted on the plurality of first electrodes 110 easily. The pluralityof organic light emitting layers 120 can be transfer printed by themethod of FIGS. 9-10.

In step (S34), the second electrode 130 is formed by coating anelectrically conductive film 1304 on a surface of a free standingsupport 1302, and then placing the electrically conductive film 1304 onthe plurality of organic light emitting layers 120. The electricallyconductive film 1304 is in direct contact with the plurality of organiclight emitting layers 120. Because part side surfaces of the pluralityof first electrodes 110 are exposed from both the patterned secondinsulative layer 140 and the plurality of organic light emitting layers120, if the second electrode 130 is formed by directly depositing, itwill cause the first electrodes 110 and the second electrode 130 beingin contact with each other and short. Parts of the second electrode 130are suspended between adjacent two of the plurality of organic lightemitting layers 120. The support 1302 can be a glass plate or a polymersheet.

FIG. 14 illustrates an organic light emitting diode array 30 of oneembodiment. The organic light emitting diode array 30 includes a base100, a plurality of first electrodes 110, a plurality of organic lightemitting layers 120, a patterned second insulative layer 140, and asecond electrode 130. The organic light emitting diode array 30 issimilar to the organic light emitting diode array 20 except that partsof the plurality of first electrodes 110 on the smooth top surfaces 109of the plurality of convexities 108 are protruded out of the patternedsecond insulative layer 140, the second electrode 130 includes a freestanding support 1302 and an electrically conductive film 1304. Thesupport 1302 is a glass, and the electrically conductive film 1304 is acontinuous indium tin oxide film.

FIGS. 15-16 illustrates a method of one embodiment for making an organiclight emitting diode array 40. The method includes following steps:

step (S40), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; the first insulative layer 106 defines a plurality ofconvexities 108 on a surface opposite to the plurality of thin-filmtransistors 104;

step (S41), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein each of the plurality of first electrodes110 is located corresponding to and electrically connected to one of theplurality of thin-film transistors 104;

step (S42), applying a plurality of organic light emitting layers 120 onthe plurality of first electrodes 110, wherein adjacent three of theplurality of organic light emitting layers 120 have different organicelectroluminescent materials;

step (S43), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 between the plurality of convexities108 and expose each of the plurality of organic light emitting layers120; and

step (S44), electrically connecting a second electrode 130 to theplurality of organic light emitting layers 120.

The method for making the organic light emitting diode array 40 issimilar to the method for making the organic light emitting diode array20 except that the plurality of convexities 108 are strip-shaped andarranged in a one-dimensional array as shown in FIG. 3, each of theplurality of convexities 108 corresponds to a row of the plurality ofthin-film transistors 104, and the second electrode 130 is comb-shaped.

In step (S41), a plurality of first electrodes 110 are located on asurface of each of the plurality of convexities 108 and spaced from eachother. In step (S42), a strip-shaped organic light emitting layers 120is transfer printed on entire surface of each of the strip-shapedconvexity 108 to cover all of the corresponding strip-shaped convexity108 and the plurality of first electrodes 110 on the correspondingstrip-shaped convexity 108. The organic light emitting diodescorresponding to the same strip-shaped convexity 108 share the commonstrip-shaped organic light emitting layers 120 and luminesce light ofthe same color. In step (S44), the comb-shaped second electrode 130includes a plurality of first strip-shaped conductors parallel with andspaced from each other, and a second strip-shaped conductorsperpendicular with and connecting the plurality of first strip-shapedconductors. Each of the plurality of first strip-shaped conductors islocated on the corresponding strip-shaped organic light emitting layers120.

FIG. 17 illustrates a method of one embodiment for making an organiclight emitting diode array 50. The method includes following steps:

step (S50), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; the first insulative layer 106 defines a plurality ofconvexities 108 on a surface opposite to the plurality of thin-filmtransistors 104;

step (S51), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein each of the plurality of first electrodes110 is located corresponding to and electrically connected to one of theplurality of thin-film transistors 104;

step (S52), applying a plurality of hole injection layers 122 on theplurality of first electrodes 110;

step (S53), transfer printing a plurality of hole transport layers 124on the plurality of hole injection layers 122, wherein adjacent three ofthe plurality of hole transport layers 124 of the same pixel unit havedifferent thickness;

step (S54), making a plurality of electroluminescent layers 125 on theplurality of hole transport layers 124, wherein adjacent three of theplurality of electroluminescent layers 125 of the same pixel unit havedifferent organic electroluminescent materials;

step (S55), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 between the plurality of convexities108 and expose each of the plurality of electroluminescent layers 125;and

step (S56), electrically connecting a second electrode 130 to theplurality of electroluminescent layers 125.

The method for making the organic light emitting diode array 50 issimilar to the method for making the organic light emitting diode array20 except that the plurality of hole injection layers 122 and theplurality of hole transport layers 124 are applied on the plurality offirst electrodes 110 before the plurality of electroluminescent layers125. The plurality of hole injection layers 122 have the same thickness,and the plurality of hole transport layers 124 have different thickness.Each of the organic light emitting layers 120 includes the holeinjection layer 122, the hole transport layer 124, and theelectroluminescent layer 125. The plurality of hole injection layers 122can be made by the method of FIG. 5 or vacuum evaporation, and theplurality of electroluminescent layers 125 can be made by the method ofFIGS. 9-10 or vacuum evaporation.

FIG. 18 illustrates a method for transfer printing the plurality of holetransport layers 124 with different thickness once time. The methodincludes following steps:

step (S530), forming a hole transport film 1242 on a surface of a fourthtemplate 156, wherein the hole transport film 1242 has differentthickness corresponding to the plurality of hole injection layers 122 ofthe same pixel unit;

step (S531), contacting the plurality of hole injection layers 122 withthe hole transport film 1242; and

step (S532), separating the plurality of hole injection layers 122 fromthe fourth template 156.

In step (S530), the hole transport film 1242 can be made byspin-coating, spray-coating, brush-coating, or immerse-coating. Thefourth template 156 has a fifth surface 1562 and a sixth surface 1564,and a seventh surface 1566. The fifth surface 1562, the sixth surface1564, and the seventh surface 1566 have different heights. In oneembodiment, the fifth surface 1562 is higher than the sixth surface1564, and the sixth surface 1564 is higher than the seventh surface1566. When the hole transport film 1242 is applied on the fourthtemplate 156, the surface of the hole transport film 1242 that isopposite to the fourth template 156 is a planar. Thus, the holetransport film 1242 on the fifth surface 1562, the hole transport film1242 on the sixth surface 1564, and the hole transport film 1242 on theseventh surface 1566 have different thickness. The method of FIG. 18 canalso be used to make the plurality of hole injection layers 122, theplurality of electroluminescent layers 125, the plurality of electrontransport layers 126 and the plurality of electron injection layers 128.

FIG. 19 illustrates an organic light emitting diode array 50 of oneembodiment. The organic light emitting diode array 50 includes a base100, a plurality of first electrodes 110, a plurality of organic lightemitting layers 120, a patterned second insulative layer 140, and asecond electrode 130. The organic light emitting diode array 50 issimilar to the organic light emitting diode array 20 except that each ofthe organic light emitting layers 120 includes the hole injection layer122, the hole transport layer 124, and the electroluminescent layer 125stacked with each other. The plurality of hole injection layers 122 havethe same thickness, the plurality of electroluminescent layers 125 havethe same thickness, and the plurality of hole transport layers 124 havedifferent thickness. Because the plurality of hole transport layers 124have different thickness, the surfaces of the plurality of holetransport layers 124 that are opposite to the plurality of holeinjection layers 122 have different heights. The surfaces of theplurality of electroluminescent layers 125 that are opposite to theplurality of hole injection layers 122 have different heights. Thus, thered light, the green light and the blue light can be mixed uniformly.

FIG. 20 illustrates an organic light emitting diode array 50A of anotherembodiment. In the organic light emitting diode array 50A, the holeinjection layer 122 is a continuous layer and covers all of theplurality of first electrodes 110. The organic light emitting diodearray 50A shares a common hole injection layer 122. The continuous holeinjection layer 122 can be made by vacuum evaporation orimmerse-coating.

FIG. 21 illustrates a method of one embodiment for making an organiclight emitting diode array 60. The method includes following steps:

step (S60), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; the first insulative layer 106 defines a plurality ofconvexities 108 with different heights;

step (S61), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein each of the plurality of first electrodes110 is located corresponding to and electrically connected to one of theplurality of thin-film transistors 104;

step (S62), applying a plurality of hole injection layers 122 and aplurality of hole transport layers 124 on the plurality of firstelectrodes 110;

step (S63), making a plurality of electroluminescent layers 125 on theplurality of hole transport layers 124, wherein adjacent three of theplurality of electroluminescent layers 125 of the same pixel unit havedifferent organic electroluminescent materials;

step (S64), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 between the plurality of convexities108 and expose each of the plurality of electroluminescent layers 125;and

step (S65), electrically connecting a second electrode 130 to theplurality of electroluminescent layers 125.

The method for making the organic light emitting diode array 60 issimilar to the method for making the organic light emitting diode array50 except that the plurality of convexities 108 have different heights,the plurality of hole injection layers 122 have the same thickness, andthe plurality of hole transport layers 124 have the same thickness. Instep (S62), the plurality of hole injection layers 122 and the pluralityof hole transport layers 124 can be made by vacuum evaporation ortransfer printing.

FIG. 22 illustrates a method for transfer printing the plurality of holeinjection layers 122 and the plurality of hole transport layers 12 oncetime. The method includes following steps:

step (S620), forming a hole transport film 1242 on a surface of a fifthtemplate 158, wherein the hole transport film 1242 has different heightscorresponding to adjacent three of the plurality of first electrodes 110of the same pixel unit;

step (S621), forming a hole injection film 1222 on a surface of the holetransport film 1242, wherein the hole injection film 1222 also hasdifferent heights corresponding to adjacent three of the plurality offirst electrodes 110 of the same pixel unit;

step (S622), contacting the plurality of first electrodes 110 with thehole injection film 1222; and

step (S623), separating the plurality of first electrodes 110 from thefifth template 158.

In step (S620), the fifth template 158 has an eighth surface 1582, aninth surface 1584, and a tenth surface 1586. The eighth surface 1582,the ninth surface 1584, and the tenth surface 1586 have differentheights. The height differences of the eighth surface 1582, the ninthsurface 1584, and the tenth surface 1586 are designed according to theheight differences of the plurality of convexities 108. The highestconvexity 108 corresponds to the lowest one of the eighth surface 1582,the ninth surface 1584, and the tenth surface 1586. When the pluralityof first electrodes 110 closes to the hole injection film 1222 on thefifth template 158, each of the plurality of first electrodes 110 can bein direct contact with the hole injection film 1222.

Both the hole injection film 1222 and the hole transport film 1242 hasuniform thickness, so that the hole injection film 1222 and the holetransport film 1242 on the eighth surface 1582, the ninth surface 1584,and the tenth surface 1586 have different heights. The adhesion strengthbetween the hole injection film 1222 and the hole transport film 1242 isgreater than the adhesion strength between the hole transport film 1242and the fifth template 158. Thus, the hole injection film 1222 and thehole transport film 1242 can be transferred from the fifth template 158to the first electrodes 110 together. A wetting layer can be appliedbetween the hole transport film 1242 and the fifth template 158. In oneembodiment, the hole transport film 1242 is baked before applying thehole injection film 1222 so that the hole transport film 1242 would notbe damaged in the wet membrane process of making the hole injection film1222. The baked hole transport film 1242 can also be further wetted inthe wet membrane process of making the hole injection film 1222.Furthermore, the hole injection film 1222 and the hole transport film1242 can be made by transfer printing twice via the method of FIG. 22.The method of FIG. 22 can also be used to made the plurality ofelectroluminescent layers 125, the plurality of electron transportlayers 126 and the plurality of electron injection layers 128.

FIG. 23 illustrates an organic light emitting diode array 60 of oneembodiment. The organic light emitting diode array 60 includes a base100, a plurality of first electrodes 110, a plurality of organic lightemitting layers 120, a patterned second insulative layer 140, and asecond electrode 130. The organic light emitting diode array 60 issimilar to the organic light emitting diode array 50 except that theplurality of convexities 108 have different heights, the plurality ofhole injection layers 122 have the same thickness, the plurality of holetransport layers 124 have the same thickness, and the plurality ofelectroluminescent layers 125 have the same thickness.

FIG. 24 illustrates an organic light emitting diode array 60A of anotherembodiment. In the organic light emitting diode array 60A, a continuouselectron transport layer 126 and a continuous electron injection layer128 are located between the plurality of electroluminescent layers 125and the second electrode 130. The organic light emitting diode array 60Ashare a common electron transport layer 126 and a common electroninjection layer 128. The electron transport layer 126 and the electroninjection layer 128 can be made by vacuum evaporation or coating.

FIG. 25 illustrates a method of one embodiment for making an organiclight emitting diode array 70. The method includes following steps:

step (S70), providing a base 100, wherein the base 100 includes asubstrate 102, a plurality of thin-film transistors 104 located on asurface of the substrate 102 and arranged to form an array, and a firstinsulative layer 106 located on a surface of the plurality of thin-filmtransistors 104; the first insulative layer 106 defines a plurality ofconvexities 108;

step (S71), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein the plurality of first electrodes 110 arelocated corresponding to and electrically connected to the plurality ofthin-film transistors 104 in a one-to-one manner;

step (S72), transfer printing a plurality of blue lightelectroluminescent layers 125 on the plurality of first electrodes 110,wherein one of the plurality of blue light electroluminescent layers 125are higher than the other two of the plurality of blue lightelectroluminescent layers 125 in each pixel unit;

step (S73), making a red light electroluminescent layers 125 and a greenlight electroluminescent layers 125 on the lower two of the plurality ofblue light electroluminescent layers 125;

step (S74), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 between the plurality of convexities108 and expose the blue light electroluminescent layer 125, the redlight electroluminescent layer 125, and the green lightelectroluminescent layer 125 of each pixel unit; and

step (S75), electrically connecting a second electrode 130 to the bluelight electroluminescent layer 125, the red light electroluminescentlayer 125, and the green light electroluminescent layer 125 of eachpixel unit.

The method for making the organic light emitting diode array 70 issimilar to the method for making the organic light emitting diode array20 except that the plurality of blue light electroluminescent layers 125with different thickness are transfer printed on the plurality of firstelectrodes 110 directly by the method of FIG. 18, and then the red lightelectroluminescent layer 125 and the green light electroluminescentlayer 125 are applied on the lower two of the plurality of blue lightelectroluminescent layers 125 respectively. The red lightelectroluminescent layer 125 and the green light electroluminescentlayer 125 can be made by vacuum evaporation, or transfer printing methodof FIGS. 9-10. The red light electroluminescent layer 125, the greenlight electroluminescent layer 125 and the highest blue lightelectroluminescent layer 125 have the same height. The blue lightelectroluminescent layers 125 of the organic light emitting diode array70 can play the function of hole injection and hole transport.Furthermore, in step (S72), a plurality of red light or green lightelectroluminescent layers 125 with different heights can be appliedfirst, and then, in step (S73), the other two kinds of different colorelectroluminescent layers 125 are formed on the lower two of theplurality of electroluminescent layers 125.

The organic light emitting diode arrays 10, 20, 20A, 30, 40, 50, 50A,60, 60A, 70 are active matrix type organic light emitting diode arrays.The methods of FIG. 1, FIG. 8, FIG. 13, FIG. 15, FIG. 17, FIG. 21 andFIG. 25 can also be used to make the passive matrix type organic lightemitting diode array.

FIG. 26 illustrates a method of one embodiment for making a passivematrix type organic light emitting diode array 80. The method includesfollowing steps:

step (S80), providing a base 100, wherein the base 100 defines aplurality of convexities 108 parallel with and spaced from each other;

step (S81), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein the plurality of first electrodes 110 areparallel with and spaced from each other, and each of the plurality offirst electrodes 110 is located on a top surface of one of the pluralityof convexities 108;

step (S82), applying a plurality of organic light emitting layers 120 onthe plurality of first electrodes 110, wherein the plurality of organiclight emitting layers 120 are located on a top surface of one of theplurality of first electrodes 110 in a one-to-one manner;

step (S83), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 and expose part of each of theplurality of organic light emitting layers 120; and

step (S84), electrically connecting a plurality of second electrodes 130to the plurality of organic light emitting layers 120, wherein theplurality of second electrodes 130 are parallel with, spaced from eachother, and extend along a direction different from the extendingdirection of the plurality of first electrodes 110.

The method for making the organic light emitting diode array 80 issimilar to the method for making the organic light emitting diode array10 except that the plurality of first electrodes 110 and the pluralityof second electrodes 130 have different structures, so that the organiclight emitting diode array 80 is passive matrix type. Furthermore, instep (S80), the base 100 can be a glass substrate, a ceramic substrate,a silicon dioxide substrate, a silicon nitride substrate or a polymersubstrate. The plurality of convexities 108 are strip-shaped and definedby the base 100.

FIGS. 27-28 illustrate a passive matrix type organic light emittingdiode array 80 of one embodiment. The organic light emitting diode array80 includes a base 100, a plurality of first electrodes 110, a pluralityof organic light emitting layers 120, a patterned second insulativelayer 140, and a plurality of second electrodes 130. The plurality ofconvexities 108 are strip-shaped, parallel with and spaced from eachother, and formed on a surface of the base 100. The plurality of firstelectrodes 110 are parallel with and spaced from each other, andcorresponds to the plurality of convexities 108 in a one-to-one manner.Each of the plurality of first electrodes 110 is located on both the topsurface and side surface of the corresponding one of the plurality ofconvexities 108, and extends to the surface of the base 100 betweenadjacent two of the plurality of convexities 108. The plurality oforganic light emitting layers 120 are strip-shaped, parallel with andspaced from each other, and located on the plurality of convexities 108in a one-to-one manner. The plurality of organic light emitting layers120 can be the same color organic light emitting layers, or differentcolor organic light emitting layers such as a blue light, a red light,and a green light. The patterned second insulative layer 140 is locatedbetween adjacent two of the plurality of convexities 108. The pluralityof second electrodes 130 extend along a direction perpendicular with theextending direction of the plurality of first electrodes 110. Aplurality of sub-pixels are defined at the places where the plurality ofsecond electrodes 130 across the plurality of first electrodes 110. Inwork, the plurality of second electrodes 130 and the plurality of firstelectrodes 110 are used as an address circuit to control the pluralityof sub-pixels.

FIG. 29 illustrates a method of one embodiment for making a passivematrix type organic light emitting diode array 90. The method includesfollowing steps:

step (S90), providing a base 100, wherein the base 100 defines aplurality of convexities 108 arranged in a two-dimensional array andspaced from each other;

step (S91), forming a plurality of first electrodes 110 on the pluralityof convexities 108, wherein the plurality of first electrodes 110 areparallel with and spaced from each other, and each of the plurality offirst electrodes 110 is located corresponding to the same row of theplurality of convexities 108;

step (S92), applying a plurality of organic light emitting layers 120 onthe plurality of first electrodes 110, wherein the plurality of organiclight emitting layers 120 are located corresponding to the plurality ofconvexities 108 in a one-to-one manner;

step (S93), making a patterned second insulative layer 140 to cover theplurality of first electrodes 110 and expose part of each of theplurality of organic light emitting layers 120; and

step (S94), electrically connecting a plurality of second electrodes 130to the plurality of organic light emitting layers 120, wherein theplurality of second electrodes 130 are parallel with, spaced from eachother, and extend along a direction different from the extendingdirection of the plurality of first electrodes 110.

The method for making the organic light emitting diode array 90 issimilar to the method for making the organic light emitting diode array80 except that the plurality of convexities 108 are arranged to form atwo-dimensional array, each of the plurality of first electrodes 110 islocated corresponding to one row of the plurality of convexities 108,and each of the plurality of organic light emitting layers 120 islocated corresponding to one of the plurality of convexities 108. Instep (S91), each of the plurality of first electrodes 110 is continuous,located on both top surface and side surface of the corresponding row ofthe plurality of convexities 108, and extends to the surface of theextends to the surface of the base 100 between adjacent two of theplurality of convexities 108.

FIG. 30 illustrates a passive matrix type organic light emitting diodearray 90 of one embodiment. The organic light emitting diode array 90includes a base 100, a plurality of first electrodes 110, a plurality oforganic light emitting layers 120, a patterned second insulative layer140 (not shown in FIG. 30), and a plurality of second electrodes 130.The plurality of convexities 108 are arranged to form a two-dimensionalarray. The plurality of first electrodes 110 are parallel with andspaced from each other, and each of the plurality of first electrodes110 is located corresponding to one row of the plurality of convexities108. The plurality of organic light emitting layers 120 are locatedcorresponding to the plurality of convexities 108 in a one-to-one mannerand located on the protrudent surfaces of the first electrode 110 on thecorresponding one of the plurality of convexities 108. The patternedsecond insulative layer 140 is located between adjacent two of theplurality of convexities 108. The plurality of second electrodes 130extend along a direction perpendicular with the extending direction ofthe plurality of first electrodes 110. A plurality of sub-pixels aredefined at the places where the plurality of second electrodes 130across the plurality of first electrodes 110. Each of the organic lightemitting layers 120 corresponds to one of the plurality of sub-pixels.The same column of organic light emitting layers 120 are the same color.In work, the plurality of second electrodes 130 and the plurality offirst electrodes 110 are used as an address circuit to control theplurality of sub-pixels.

The embodiments shown and described above are only examples. Even thoughnumerous characteristics and advantages of the present technology havebeen set forth in the foregoing description, together with details ofthe structure and function of the present disclosure, the disclosure isillustrative only, and changes may be made in the detail, including inmatters of shape, size and arrangement of the parts within theprinciples of the present disclosure up to, and including, the fullextent established by the broad general meaning of the terms used in theclaims.

What is claimed is:
 1. A method of making organic light emitting diodearray, the method comprising: providing a base defining a plurality ofconvexities spaced from each other; forming a plurality of firstelectrodes on the plurality of convexities, wherein the plurality offirst electrodes are divided into a first group, a second group, and athird group; transfer printing a plurality of electroluminescent layerson the plurality of first electrodes, wherein transfer printing theplurality of electroluminescent layers comprises: applying a firstelectroluminescent film on a first template; contacting the first groupof the plurality of first electrodes with the first electroluminescentfilm; separating the first group of the plurality of first electrodesfrom the first template so that a plurality of first electroluminescentlayers are formed on the first group of the plurality of firstelectrodes; applying a second electroluminescent film on a secondtemplate; contacting the second group of the plurality of firstelectrodes with the second electroluminescent film; separating thesecond group of the plurality of first electrodes from the secondtemplate so that a plurality of second electroluminescent layers areformed on the second group of the plurality of first electrodes;applying a third electroluminescent film on a third template; contactingthe third group of the plurality of first electrodes with the thirdelectroluminescent film; separating the third group of the plurality offirst electrodes from the third template so that a plurality of thirdelectroluminescent layers are formed on the third group of the pluralityof first electrodes; making a patterned second insulative layer to coverthe plurality of first electrodes and expose the plurality ofelectroluminescent layers; and electrically connecting at least onesecond electrode to the plurality of electroluminescent layers.
 2. Themethod of claim 1, wherein the base comprises a substrate; a pluralityof thin-film transistors, located on a surface of the substrate andarranged to form an array; and a first insulative layer, located on asurface of the plurality of thin-film transistors and defining theplurality of convexities.
 3. The method of claim 2, wherein theplurality of convexities are arranged in an array and corresponds to theplurality of thin-film transistors in a one-to-one manner; and theplurality of first electrodes are formed on the plurality of convexitiesin a one-to-one manner.
 4. The method of claim 2, wherein the pluralityof convexities are strip-shaped and in parallel with each other; each ofthe plurality of convexities is located corresponding to one row of theplurality of thin-film transistors; and more than two of the pluralityof first electrodes are formed on each of the plurality of convexities.5. The method of claim 2, wherein the forming the plurality of firstelectrodes on the plurality of convexities comprises: exposing part ofeach of the plurality of thin-film transistors by etching the base fromthe first insulative layer; depositing a continuous conductive layer tocover the plurality of convexities and electrically connect to theplurality of thin-film transistors; patterning the continuous conductivelayer to obtain the plurality of first electrodes spaced from eachother; and the plurality of first electrodes correspond to and areelectrically connected to the plurality of thin-film transistors in aone-to-one manner.
 6. The method of claim 5, wherein each of theplurality of first electrodes is located at least on a top surface and aside surface of one of the plurality of convexities, and extend tosurfaces of the base that are between the plurality of convexities. 7.The method of claim 1, wherein the first electroluminescent film is ared light organic electroluminescent film; the second electroluminescentfilm is a green light organic electroluminescent film; and the thirdelectroluminescent film is a blue light organic electroluminescent film.8. The method of claim 1, wherein the applying the firstelectroluminescent film on the first template comprises coating thefirst electroluminescent film only on parts of the first template thatcorrespond to the first group of the plurality of first electrodes; theapplying the second electroluminescent film on the second templatecomprises coating the second electroluminescent film only on parts ofthe second template that correspond to the second group of the pluralityof first electrodes; and the applying the third electroluminescent filmon the third template comprises coating the third electroluminescentfilm only on parts of the third template that correspond to the thirdgroup of the plurality of first electrodes.
 9. The method of claim 1,wherein the contacting the first group of the plurality of firstelectrodes with the first electroluminescent film comprises spacing thesecond and third groups of the plurality of first electrodes from thefirst electroluminescent film; the contacting the second group of theplurality of first electrodes with the second electroluminescent filmcomprises spacing the first and third groups of the plurality of firstelectrodes from the second electroluminescent film; and the contactingthe third group of the plurality of first electrodes with the thirdelectroluminescent film comprises spacing the first and second groups ofthe plurality of first electrodes from the third electroluminescentfilm.
 10. The method of claim 9, wherein the first template has a firstsurface corresponding to the first group of the plurality of firstelectrodes and a second surface lower than the first surface andcorresponding to the second and third groups of the plurality of firstelectrodes; the second template has a third surface corresponding to thesecond group of the plurality of first electrodes and a fourth surfacelower than the third surface and corresponding to the first and thirdgroups of the plurality of first electrodes; and the third template hasa fifth surface corresponding to the third group of the plurality offirst electrodes and a sixth surface lower than the fifth surface andcorresponding to the first and second groups of the plurality of firstelectrodes.
 11. The method of claim 1, further comprising transferprinting a plurality of hole injection layers and a plurality of holetransport layers on the plurality of first electrodes before transferprinting the plurality of electroluminescent layers on the plurality offirst electrodes.
 12. The method of claim 11, further comprising makinga plurality of electron transport layers and a plurality of electroninjection layers on the plurality of electroluminescent layers aftertransfer printing the plurality of electroluminescent layers on theplurality of first electrodes.
 13. The method of claim 1, furthercomprising applying a continuous hole injection layer and a continuoushole transport layer on the plurality of first electrodes beforetransfer printing the plurality of electroluminescent layers on theplurality of first electrodes.
 14. The method of claim 13, furthercomprising making a continuous electron transport layer and a continuouselectron injection layer on the plurality of electroluminescent layersafter transfer printing the plurality of electroluminescent layers onthe plurality of first electrodes.
 15. A method of making organic lightemitting diode array, the method comprising: providing a base defining aplurality of convexities spaced from each other; forming a plurality offirst electrodes on the plurality of convexities, wherein the pluralityof first electrodes are parallel with each other and extend along afirst direction; and the plurality of first electrodes are divided intoa first group, a second group, and a third group; transfer printing aplurality of electroluminescent layers on the plurality of firstelectrodes, wherein transfer printing the plurality ofelectroluminescent layers comprises: applying a first electroluminescentfilm on a first template; contacting the first group of the plurality offirst electrodes with the first electroluminescent film; separating thefirst group of the plurality of first electrodes from the first templateso that a plurality of first electroluminescent layers are formed on thefirst group of the plurality of first electrodes; applying a secondelectroluminescent film on a second template; contacting the secondgroup of the plurality of first electrodes with the secondelectroluminescent film; separating the second group of the plurality offirst electrodes from the second template so that a plurality of secondelectroluminescent layers are formed on the second group of theplurality of first electrodes; applying a third electroluminescent filmon a third template; contacting the third group of the plurality offirst electrodes with the third electroluminescent film; separating thethird group of the plurality of first electrodes from the third templateso that a plurality of third electroluminescent layers are formed on thethird group of the plurality of first electrodes; making a patternedsecond insulative layer to cover the plurality of first electrodes andexpose the plurality of electroluminescent layers; and electricallyconnecting a plurality of second electrodes to the plurality ofelectroluminescent layers, wherein the plurality of second electrodesare parallel with each other and extend along a second directiondifferent from the first direction.
 16. The method of claim 15, whereinthe plurality of convexities are strip-shaped, parallel with and spacedfrom each other, and the plurality of first electrodes are parallel withand spaced from each other, and corresponds to the plurality ofconvexities in a one-to-one manner.
 17. The method of claim 15, whereinthe plurality of convexities are arranged to form a two-dimensionalarray, each of the plurality of first electrodes is locatedcorresponding to one row of the plurality of convexities, and theplurality of electroluminescent layers is located corresponding to theplurality of convexities in a one-to-one manner.
 18. The method of claim15, wherein the applying the first electroluminescent film on the firsttemplate comprises coating the first electroluminescent film only onparts of the first template that correspond to the first group of theplurality of first electrodes; the applying the secondelectroluminescent film on the second template comprises coating thesecond electroluminescent film only on parts of the second template thatcorrespond to the second group of the plurality of first electrodes; andthe applying the third electroluminescent film on the third templatecomprises coating the third electroluminescent film only on parts of thethird template that correspond to the third group of the plurality offirst electrodes.
 19. The method of claim 15, wherein the contacting thefirst group of the plurality of first electrodes with the firstelectroluminescent film comprises spacing the second and third groups ofthe plurality of first electrodes from the first electroluminescentfilm; the contacting the second group of the plurality of firstelectrodes with the second electroluminescent film comprises spacing thefirst and third groups of the plurality of first electrodes from thesecond electroluminescent film; and the contacting the third group ofthe plurality of first electrodes with the third electroluminescent filmcomprises spacing the first and second groups of the plurality of firstelectrodes from the third electroluminescent film.
 20. A method ofmaking organic light emitting diode array, the method comprising:providing a base defining a plurality of convexities spaced from eachother; forming a plurality of first electrodes on the plurality ofconvexities, wherein the plurality of first electrodes are divided intoa first group, a second group, and a third group; transfer printing aplurality of electroluminescent layers on the plurality of firstelectrodes, wherein transfer printing the plurality ofelectroluminescent layers comprises: transfer printing a plurality ofred light electroluminescent layers on the first group of the pluralityof first electrodes; transfer printing a plurality of green lightelectroluminescent layers on the second group of the plurality of firstelectrodes; transfer printing a plurality of blue lightelectroluminescent layers on the third group of the plurality of firstelectrodes; making a patterned second insulative layer to cover theplurality of first electrodes and expose the plurality ofelectroluminescent layers; and electrically connecting at least onesecond electrode to the plurality of electroluminescent layers.